Wing-drive mechanism and vehicle employing same

ABSTRACT

A wing-drive mechanism is described that permits, with proper control, movement of a wing about multiple wing trajectories. The wing-drive is capable of independent movement about three rotational degrees of movement; movement about a flap axis is independent of movement about a yaw axis, and both are independent of changes in the pitch of the wing. Methods of controlling the wing-drive mechanism to affect a desired wing trajectory include the use of a non-linear automated controller that generates input signals to the wing-drive mechanism by comparing actual and desired wing trajectories in real time. Specification of wing trajectories is preferably also accomplished in real time using an automated trajectory specification system, which can include a fuzzy logic processor or a neural network.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of U.S. provisional application No.60/277,356, filed Mar. 19, 2001.

BACKGROUND OF THE INVENTION

This invention relates to vehicles that derive motion from one or moreflapping wings.

One approach to heavier-than-air flight employs flapping wings togenerate a combined lift-thrust force. In principle, flapping wingtechnology offers the possibility of creating versatile flight vehiclesthat can combine and in some cases exceed the performance advantages offixed-wing and rotary-wing technologies. In particular, flapping wingtechnology offers the possibility of providing improved maneuverabilitycompared to even rotary-wing technologies. Vehicles employing flappingwing technologies are referred to as “ornithopters”.

Unfortunately, very few ornithopters have succeeded in flying. In 1929,Lippisch developed a human-powered ornithopter that achievednon-sustained flight. In 1986, MacCready et al. developed an ornithoptermodeled on a pterosaur, an extinct flying reptile. That ornithopter waswinch launched and could not sustain flight for an extended duration.More recently, Harris and DeLaurier developed an ornithopter that wascapable of sustained flight. In addition, various toys have beendeveloped that employ flapping wing technology to fly, including thatdescribed in U.S. Pat. No. 4,729,728 to Van Ruymbeke.

Unfortunately, even those previous ornithopters that were capable offlight were very limited in their maneuverability. These ornithoptersoperated by flapping wings only in a single trajectory, i.e., in an upand down motion. Thus, the aerodynamic force developed by the flappingwings over the course of a series of “beats” was fixed in a fixed(relative to the vehicle), substantially vertical plane. To developlift, these ornithopters mimicked conventional fixed wing aircraft inthat in all cases lift was achieved by creating airflow past an airfoildue to the forward motion of the vehicle as a whole. Thus, theseornithopters suffered from the same maneuverability limitations asconventional fixed-wing aircraft.

In an analogous way, conventional and submersible watercraft, spacecraftand satellites also are limited in their maneuverability due to thedesign of their propulsion systems.

In U.S. Pat. No. 6,206,324, U.S. patent application Ser. No. 09/793,333and PCT/US00/23544, all to Michael J. C. Smith, a wing-drive mechanismis described, together with methods for controlling the wing-drivemechanism to effect flight. The wing-drive mechanism described in thepatents and the applications is capable of independent movement aboutflap, pitch and yaw axes through the operation of three axis drivemechanisms.

It is desirable to provide a wing-drive that operates smoothly andefficiently, and which preferably is light in weight.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE is an isometric view of an embodiment of this invention.

SUMMARY OF THE INVENTION

In one aspect, this invention is a wing-drive mechanism for a vehiclehaving a fuselage, comprising

a) an outwardly extending spar that is rotatable independently in flap,yaw and pitch directions about a pivot point;

b) an inwardly extending spar that is rotatable independently in flap,yaw and pitch directions about the pivot point,

c) a drive wing mounted on the outwardly extending spar;

d) a first axis drive mechanism for moving said drive wing about thepivot point in a flap direction in response to a first movement inputsignal;

e) a second axis drive mechanism for moving said drive wing about thepivot point in a yaw direction in response to a second movement inputsignal, wherein said second axis drive mechanism operates independentlyof said first axis drive mechanism; and

f) a third axis drive mechanism for adjusting the pitch of said drivewing in response to a third movement input signal, wherein said thirdaxis drive mechanism operates independently of said first and secondaxis drive mechanisms,

wherein at least one of the first and second axis drive mechanisms acton the inwardly extending spar to effect movement of the inwardlyextending spar, the outwardly extending spar and the drive wing aboutthe pivot point.

The wing-drive mechanism of this invention is capable of particularlysmooth and accurate operation, can be quite light in weight if desired,and is of simple construction. Because the wing-drive mechanism of thisinvention is capable of independent movement in three degrees ofrotation, it can with proper control be operated to move over multipletrajectories. Multiple, arbitrary wing trajectories can be produced byvarying the relative operation of the three axis drive mechanisms,thereby permitting the drive-wing to generate, over the course of a“beat” or series of beats, a net force vector that can have varyingmagnitudes and directions relative to the orientation of the fuselage inspace.

The wing-drive mechanism of this invention also allows for thedevelopment of vehicles having two or more independently operated drivewings; i.e. the trajectory of one drive wing can be specifiedarbitrarily with respect to the trajectory of another drive wing. Byoperating independently in this fashion, the forces generated by eachdrive wing can be combined in various ways to maneuver the vehicle. Asdiscussed below, the wing-drive mechanism of this invention mostpreferably operates independently of the orientation of the fuselage ininertial space, i.e. the ability of the wing-drive mechanism to affect acertain trajectory relative to an inertial frame of reference is notconditioned on the vehicle occupying a unique orientation in space. Thiscan provide yet further refinements in maneuverability and control.

Unless the context requires a narrow meaning, the terms “wing” or “drivewing” are used herein broadly to mean any wing, aileron, stabilizer,rudder, paddle or other propulsion and/or steering device that is movedthrough a trajectory by the wing-drive mechanism of the invention.“Fuselage” is used herein as shorthand for any host body to which thewing-drive mechanism is affixed.

DETAILED DESCRIPTION OF THE INVENTION

In this invention, a vehicle has one or more movable drive wings thatare attached directly or indirectly to a fuselage. The vehicle can be,for example, a flying vehicle such as an ornithopter, a watercraft suchas a submersible or a boat, a spacecraft or a satellite. As used herein,the term “fuselage” refers to a structure to which the drive wings areattached, and in relation to which the drive wings move during a beatcycle. The “fuselage” can have any arbitrary shape, size andorientation, and may optionally include one or more platforms orenclosed spaces for carrying operational systems, cargo and/orpassengers. Wings and drive wings for flying vehicles are of particularinterest.

In the context of this application, “drive wing” means an appendageattached directly or indirectly to the fuselage of the vehicle, andwhich moves relative to the fuselage to create a force that impartsmotion or navigational control (or both) to the vehicle in apredetermined direction. In the case of an aircraft, the drive wing cantake the form of, e.g., a fixed wing, rotary wing, airfoil, rudder,stabilizer, elevator, aileron, leg, or landing gear. In the case of awatercraft, the drive wing can take the form of, e.g., a rudder,propulsion device, tail (analogous to the tail of a fish or aquaticmammal) or fin (again analogous to a fish or aquatic mammal). In thecase of a spacecraft or satellite, the drive wing can be adapted toprovide an inertial control system, or to provide mass balancing.

The wing-drive mechanism of the invention is characterized in that thedrive wing can move simultaneously and independently in three rotationaldegrees of freedom relative to the fuselage, as described more fullyhereinafter. For each drive wing, there are independent axis drivemechanisms for moving the drive wing about a flap axis and a yaw axis.There is another independent axis drive mechanism for changing the pitchof the drive wing. In this context, the axis drive mechanisms are saidto operate “independently” if the motion imparted to the drive wing byeach individual axis drive mechanism can be specified arbitrarily withrespect to the motions imparted to the drive wing by the other axisdrive mechanisms.

In this invention, at least one of the first and second axis drivemechanisms, preferably the first axis drive mechanism, and morepreferably both, effect movement of the drive wing by effecting motionof the inwardly extending spar.

The flap and yaw axes are advantageously fixed with respect to theorientation of the fuselage. Provided that the yaw and flap axes are notcoincident or parallel, they can have any relative orientation thatallows for the drive wing to move up-and-down relative to an inertialframe of reference, backward-and-forward (or side-by-side) relative tothe fuselage, and in any combination of up-and-down andbackward-and-forward (or side to side). Note that the descriptors “flap”and “yaw” are arbitrary, as are the orientation of the “yaw” and “flap”axes relative to the fuselage. For design purposes, however, the “flap”axis is preferably substantially horizontal (for example +/− up to about45° from horizontal) and the “yaw” axis is preferably substantiallyvertical (for example +/− up to about 45° from vertical) when thefuselage is in a nominally “ordinary” orientation during flight. It isnot necessary that the flap and yaw axes be perpendicular to each other,although an angle of from about 45-90° is preferred, an angle of about60-90° is more preferred and an angle of about 90° is most preferred. Inthe embodiment shown in the FIGURE, the flap axis is substantiallyhorizontal and parallel with the nominal front-to-rear orientation offuselage 100 (shown in outline), and the yaw axis is substantiallyvertical and perpendicular to the front-to-rear orientation of fuselage100.

The FIGURE illustrates an embodiment of a wing-drive mechanism accordingto the invention, in which both the first and second axis drivemechanisms move the drive wing by acting on an inwardly extending spar.Drive wing 101 is affixed to outwardly extending spar 102. Outwardlyextending spar 102 is rotatable about pivot point 104 in flap, yaw andpitch directions. The wing-drive mechanism is affixed to fuselage 100through pivot point 104 in such a way that outwardly extending spar 102and inwardly extending spar 117 can each move independently in flap, yawand pitch directions. As shown, pivot point 104 is in the form of aball; a corresponding socket-type holder affixed to the fuselage permitsthe spar to move in the required manner. However, any means of affixingthe wing-drive mechanism directly or indirectly to the fuselage so thatinwardly extending spar 117 and outwardly extending spar can move aboutpivot point 104 can be used.

Inwardly extending spar 117 is similarly rotatable about pivot point104.

Note that the use of the term “spar” in this application is not intendedto specify any particular shape or configuration. The inwardly extendingspar is simply a member that is connected to the pivot point and is incommunication with the axis drive mechanisms so that actuation of one ormore of the axis drive mechanisms effects rotation of outwardlyextending spar about the pivot point. Similarly, the outwardly extendingspar is simply a member that is connected to the pivot point and to thedrive wing so that movement of the inwardly extending spar by one ormore of the axis drive mechanisms effects rotation of the drive wingabout the pivot point. The inwardly extending spar and outwardlyextending spar may be formed as a single piece if desired. The outwardlyextending spar may be integrally formed into the drive wing. Either maybe of any shape and size that permits it to perform the functionsdescribed herein.

Axis drive mechanisms 103, 111 and 121 interact with inwardly extendingspar to rotate it in pitch, flap and yaw directions, respectively. Thisin turn causes corresponding pitch, flap and yaw movements of outwardlyextending spar 102 and drive wing 101. As shown, third axis drivemechanism 103 consists of motor 161 that is affixed to inwardlyextending spar 117. Motor 161 is slotted onto guide rail 120 in such away that (1) motor 161 can move freely along slot 122, (2) motor 161 isrotationally fixed with respect to guide rail 120, and (3) inwardlyextending spar 117 (which forms or is affixed to the shaft of motor 161)can rotate freely with respect to guide rail 120. When activated, motor161 rotates inwardly extending spar 117 about pitch axis 105 in thedirection indicated by the double-headed arrow a-a′. Rotation aboutpitch axis 105 results in rotation of outwardly extending spar 102 and,correspondingly, a variation of the pitch of drive wing 101.

A flap motion is imparted to drive wing 101 via first axis drivemechanism 111. First axis drive mechanism 111 provides torque toinwardly extending spar 117 about flap axis 113. In the embodimentshown, torque is transferred to inwardly extending spar 117 via guiderail 110. As shown, guide rail 110 is in the form of a slotted arc, andinwardly extending spar 117 is inserted through slot 112 of guide rail110. First axis drive mechanism 111 is adapted to apply torque to guiderail 110, thereby rotating guide rail 110 and inwardly extending spar117 about flap axis 113 to impart an oscillating flap motion tooutwardly extending spar 102 and drive wing 101. The orientation of flapaxis 113 is fixed in space with respect to fuselage 100 by virtue offirst axis drive mechanism 111 being affixed directly or indirectly tofuselage 100. The direction of rotation imparted by first axis drivemechanism 111 to guide rail 110 is shown by double-headed arrow b-b′. Aclockwise rotation (as seen facing the “rear” of the fuselage) isarbitrarily designated as “positive”, and the opposite rotation isarbitrarily designated as “negative”. The direction of flap motionimparted to drive wing 101 is shown by double-headed arrow B-B′.

A yaw motion is imparted to drive wing 101 via second axis drivemechanism 121. Second axis drive mechanism 121 provides torque toinwardly extending spar 117 about yaw axis 123. In the embodiment shown,torque is transferred to inwardly extending spar 117 via guide rail 120.As shown, guide rail 120 is in the form of a slotted arc, and inwardlyextending spar 117 is inserted through slot 122 of guide rail 120. Inthis embodiment the radius of curvature of guide rail 120 is larger thanthat of guide rail 110, so that the two guide rails can move freely andindependently with respect to each other. The direction of rotationimparted by second axis drive mechanism 121 to guide rail 120 is shownby double-headed arrow c-c′. Second axis drive mechanism 121 is adaptedto apply torque to guide rail 120, thereby rotating guide rail 120 andinwardly extending spar 117 about flap axis 123 to impart an oscillatingflap motion to outwardly extending spar 102 and drive wing 101. Aclockwise rotation (as seen facing “upward” through the fuselage) isarbitrarily designated as “positive”, and the opposite rotation isarbitrarily designated as “negative”. The direction of yaw motionimparted to drive wing 101 is shown by double-headed arrow C-C′.

In the FIGURE, optional mass balance 106 is affixed to inwardlyextending spar 117 to offset the mass of wing 101 and outwardlyextending spar 102, so as to improve operation, improve balance, and toreduce the energy needed to operate the wing-drive mechanism.

Axis drive mechanisms 103, 111 and 121 affect movement of drive wing 101by providing torque indirectly to outwardly extending spar 102 about thepitch, flap and yaw axes. In response to a movement input signal, eachof axis drive mechanisms 103, 111 and 121 (1) transfer torque to drivewing 101 (2) independently of the operation of the other axis drivemechanisms. As such, axis drive mechanisms 103, 111 and 121 each includemeans for receiving a movement input signal and applying torque inresponse thereto, as well as coupling apparatus for transferring thetorque to spar 102. Axis drive mechanisms 103, 111 and 121 also includeor are coupled to a source of mechanical power such as a motor. It willbe readily appreciated that a great many variations in the designs andconfigurations of the axis drive mechanisms are possible.

In the embodiment shown in the FIGURE, mechanical power is supplied toaxis drive mechanisms 103, 111 and 121 by motors 161, 171 and 181,respectively. Such motors can be of any type, including but not limitedto internal combustion engines, pneumatic motors, steam engines,hydraulic motors, electrical motors and hybrid electrical motors.Electrical motors are preferred, as the use of an electrical motor formechanical power greatly facilitates the creation of complex torquesequences over the course of a beat cycle. Electrical motors thatoperate bi-directionally are especially preferred as such motors tend tobe light weight and offer the possibility of controlling the magnitudeand direction of the applied torque through variations in the electricalpower supply to the motor.

Piezoelectric actuators can be used to supplement or replace theaforementioned motors. These actuators include a material, commonly aceramic material such as lead titanate, lead zirconate titanate, leadmagnesium niobate, lead metaniobate, lead zirconate and the like thatbecome reversibly distorted in a predetermined direction when anelectric current is applied. Piezoelectric actuators are well known andcommercially available. Actuators such as BM1110-400, BM1110-532,BM1120-400, BM1120-532, BM1125-400 and BM1125-532, all sold by SensorTechnology, Ltd., Ontario Canada, are suitable.

Although each axis drive mechanism shown in The FIGURE has its ownsource of mechanical power, it is possible through appropriate linkagesfor two or more axis drive mechanisms to share a single mechanical powersource.

Axis drive mechanisms 103, 111 and 121 also contain connections to fuelor power supplies. If an axis drive mechanism does not contain adedicated source of mechanical power, it is coupled to one. Suitablepower supplies include fossil fuels, compressed gasses, steam,batteries, hydrogen fuel cells, solar panels, generators or combinationsof these.

The combined operations of axis drive mechanisms 103, 111 and 121 movedrive wing 101 through its trajectory. The trajectory produced throughthe combined operations of axis drive mechanisms 103, 111 and 121 can bealtered through changes in the frequency, sequencing, phasing andmagnitude of the flap, yaw and pitch motions, or through combinations ofsuch changes. The ability of the wing-drive mechanism to affect multipletrajectories is an important advantage of this invention, and is aresult of employing a wing-drive mechanism that permits the drive wingto move over three independent rotational degrees of freedom. Bychanging the drive wing trajectory, both the magnitude and the directionof the net force (relative to the fuselage or an inertial frame ofreference, or both) created by the drive wing over the course of a beatcycle or series of beat cycles can be varied in a predetermined way.

Flap, yaw and pitch motions are affected by the application of torque todrive wing 101 by each of axis drive mechanisms 103, 111 and 121. Toaffect a specific drive wing trajectory, each of axis drive mechanisms103, 111 and 121 apply torque, over the course of a beat cycle, in apredetermined pattern. Generally, the torque applied by each of axisdrive mechanisms 103, 111 and 121 changes in a continuous or piecewisecontinuous manner over the course of beat cycle. To maintain a specificdrive wing trajectory, those torque patterns are simply repeated overmultiple beat cycles. Changes in drive wing trajectory are affected byaltering the pattern of torque that is applied by at least one andpossibly two or three of the axis drive mechanisms 103, 111 or 121.

Suitable springs may also be inserted between the drive-axis shafts andthe drive-motor fuselage bases to act as inertial energy storage devicesand to supplement the mass balance weights. This is shown in The FIGUREat reference numerals 134 and 144. Also, the drive motors may be doubledup by placing motors on either side of the slotted-arc rails. Anotherpitch control motor may be placed in parallel or in series with theexisting pitch control motor. In addition, guide rails 110 and 120 maybe doubled up as a fail-safe measure.

In another modification of the embodiment shown in the FIGURE, therelative positions of motor 161 and mass balance 106 may be reversed, sothat motor 161 resides between pivot point 104 and guide rails 110 and120, and mass balance 106 resides so that the guide rails are interposedbetween mass balance 106 and motor 161. Motor 161 is slotted onto guiderail 110 in such a way that (1) motor 161 can move freely along slot112, (2) motor 161 is rotationally fixed with respect to guide rail 110,and (3) inwardly extending spar 117 (which forms or is affixed to theshaft of motor 161) can rotate freely with respect to guide rail 110. Inyet other alternatives, mass balance 106 and motor 161 can be placed onthe same side of the guide rails, with the motor 161 and mass balance106 slotted onto guide rail 110 if they are between the guide rails andthe pivot point, or the motor 161 and mass balance 106 slotted ontoguide rail 120 if the guide rails are between the pivot point and themotor-mass balance combination.

U.S. Pat. No. 6,206,324, U.S. patent application Ser. No. 09/793,333 andPCT/US00/23544all to Michael J. C. Smith and all incorporated herein byreference in their entirety, describe methods for controlling themovement of a wing-drive mechanism having three independent axis drivemechanisms that provide independent movement about flap, yaw and pitchaxes. Those methods are entirely suitable for controlling the wing-drivemechanism of this invention. In general, in order to affect a givendrive wing trajectory, it is necessary to create a set of coordinatedtorque patterns that are to be applied by each of the axis drivemechanisms over a course of a beat cycle. Control over the wing-drivemechanism of this invention is exercised by (1) identifying a desireddrive wing trajectory and (2) generating and transmitting movement inputsignals which actuate the respective axis drive mechanisms to supply theappropriate torque sequences to affect the desired drive wingtrajectory. Desired wing trajectories can be identified by an automatedtrajectory specification system (ATSS) as described in the Smith patentand applications mentioned above. The ATSS can specify the trajectory toa controller that computes torques to be applied to each of the first,second and third axis drive mechanisms to effect the desired wingtrajectory, again as described in the aforementioned Smith patent andapplications.

The controller is preferably one that generates said first, second andthird movement input signals by calculating said first, second and thirdmovement input signals in real time using a controlling function thatrelates a desired drive wing trajectory and an actual drive wingtrajectory to torques to be applied by each of said first, second andthird axis drive mechanisms. The controller preferably specifies thedesired drive wing trajectory and the actual drive wing trajectory asdrive wing orientation parameters, drive wing rate of change orientationparameters, drive wing rate of change of rate of change of orientationparameters, or a combination of two or more of these.

The automated trajectory specification system preferably specifies thedesired drive wing trajectory and said actual drive wing trajectory tothe controller as one or more values representing the difference betweensaid desired drive-wing trajectory and said actual drive wingtrajectory. The automated trajectory specification system preferablygenerates said desired drive wing trajectory by comparing inputtedactual and desired data that is selected from the group consisting ofvehicle position, velocity, acceleration, orientation, rate of change oforientation, rate of change of rate of change of orientation andcombinations of two or more thereof. The automated trajectoryspecification system preferably includes a fuzzy logic processor or aneural network.

It will be appreciated that many modifications can be made to thewing-drive mechanism as described herein without departing from thespirit of the invention, the scope of which is defined by the appendedclaims. For example, redundant systems may be employed as a hedgeagainst failure of a particular component.

What is claimed is:
 1. A wing-drive mechanism for a vehicle having afuselage, comprising a) an outwardly extending spar that is rotatableindependently in flap, yaw and pitch directions about a pivot point; b)an inwardly extending spar that is rotatable independently in flap, yawand pitch directions about the pivot point, c) a drive wing mounted onthe outwardly extending spar; d) a first axis drive mechanism for movingsaid drive wing about the pivot point in a flap direction in response toa first movement input signal; e) a second axis drive mechanism formoving said drive wing about the pivot point in a yaw direction inresponse to a second movement input signal, wherein said second axisdrive mechanism operates independently of said first axis drivemechanism; and f) a third axis drive mechanism for adjusting the pitchof said drive wing in response to a third movement input signal, whereinsaid third axis drive mechanism operates independently of said first andsecond axis drive mechanisms, wherein at least one of the first andsecond axis drive mechanisms act on the inwardly extending spar toeffect movement of the inwardly extending spar, the outwardly extendingspar and the drive wing about the pivot point.
 2. The wing-drivemechanism of claim 1 wherein the first axis drive mechanism acts on theinwardly extending spar to effect movement of the inwardly extendingspar, the outwardly extending spar and the drive wing about the pivotpoint.
 3. The wing-drive mechanism of claim 1 wherein the second axisdrive mechanism acts on the inwardly extending spar to effect movementof the inwardly extending spar, the outwardly extending spar and thedrive wing about the pivot point.
 4. The wing-drive mechanism of claim 2wherein the second axis drive mechanism acts on the inwardly extendingspar to effect movement of the inwardly extending spar, the outwardlyextending spar and the drive wing about the pivot point.
 5. Thewing-drive mechanism of claim 1 wherein said wing-drive mechanismfurther comprises a controller that generates said first, second andthird movement input signals by calculating said first, second and thirdmovement input signals in real time using a controlling function thatrelates a desired drive wing trajectory and an actual drive wingtrajectory to torques to be applied by each of said first, second andthird axis drive mechanisms.
 6. The wing-drive mechanism of claim 5,wherein said controller specifies said desired drive wing trajectory andsaid actual drive wing trajectory as drive wing orientation parameters,drive wing rate of change orientation parameters, drive wing rate ofchange of rate of change of orientation parameters, or a combination oftwo or more of these.
 7. The wing-drive mechanism of claim 6, whereinsaid wing-drive mechanism further comprises an automated trajectoryspecification system that specifies the desired drive wing trajectoryand said actual drive wing trajectory to the controller.
 8. Thewing-drive mechanism of claim 7, wherein said desired drive-wingtrajectory and said actual drive wing trajectory are specified to thecontroller as one or more values representing the difference betweensaid desired drive-wing trajectory and said actual drive wingtrajectory.
 9. The wing-drive mechanism of claim 7, wherein saidautomated trajectory specification system generates said desired drivewing trajectory by comparing inputted actual and desired data that isselected from the group consisting of vehicle position, velocity,acceleration, orientation, rate of change of orientation, rate of changeof rate of change of orientation and combinations of two or morethereof.
 10. The wing-drive mechanism of claim 7 wherein said automatedtrajectory specification system includes a fuzzy logic processor or aneural network.
 11. The wing drive mechanism of claim 4 wherein theinwardly extending spar is inserted through a slot of a first slottedarc in said first axis drive mechanism, said first slotted arc beingrotatable about said flap axis, such that rotation of said first slottedarc about said flap axis imparts a flap motion to said drive wing. 12.The wing-drive mechanism of claim 11, wherein the inwardly extendingspar is inserted through a slot of a second slotted arc in said secondaxis drive mechanism, said second slotted arc being rotatable about saidyaw axis, such that rotation of said second slotted arc about said yawaxis imparts a yaw motion to said drive wing.